Surface Segregation of Molybdenum During Pitting Corrosion of a Nickel-Molybdenum Alloy

Thin film samples of single-phase nickel-13 Wt% molybdenum alloy have been subjected to a localized pitting attack in chloride-containing solution. On subsequent analysis by scanning transmission electron microscopy using a variety of examination modes, it is observed that crystallographic pits are formed in the foil and that a molybdenum rich phase accumulates preferentially within the pits. The levels of chloride concentration on the pitted sample surface are below those detectable by the instrument.